In the pharmaceutical industry, a machine for filling capsules with a powdered pharmaceutical product is known comprising a conveying device, which is movable continuously along a given path and has a number of pockets, each for receiving a respective bottom shell of a relative capsule; a container containing the product; and a metering wheel mounted to rotate continuously about a respective longitudinal axis.
The metering wheel has a number of metering devices, each of which is movable with the metering wheel along a portion of said path, in time with a relative bottom shell, to withdraw the product from said container and feed the product into the bottom shell, and comprises a cylinder and a piston moving vertically with respect to each other.
The cylinder and piston are moved with respect to each other by respective actuating devices, each of which comprises at least one cam located over said container, and at least one tappet cooperating with the cam. The piston actuating device also comprises at least one spring fitted to the piston and interposed between the piston and the cylinder to keep the relative tappet normally in contact with the relative cam.
At the end of each operating cycle of the machine, the powdered pharmaceutical product scattered about the metering wheel must be stabilized to prevent it being inhaled by machine maintenance and cleaning personnel.
Since the product is stabilized by spraying water on the metering wheel and, therefore, on the actuating devices, known machines of the above type have several drawbacks, mainly due to the fact that, to prevent corrosion and rusting, the cams, tappets, and springs of the metering devices must be made of stainless steel, have a relatively short working life, and require frequent maintenance.
Another drawback of known machines of the above type lies in the presence and size of the cams seriously impairing the effectiveness of the product stabilizing and machine washing operations.